[abe-nv]

Problem

The hierarchical update-time scan only follows #include lines. An entry point compiled with Slang is therefore not rebuilt when a module it imports changes, and projects end up working around it with blocks like

#if 0
#include "Module.slang"   // dependency tracking only
#endif

in their entry-point files.

Change

For Slang sources (--slang, or .slang / .slangh files) the scan also follows

• import Foo; and __exported import Foo;
• import Foo.Bar; (resolved as Foo/Bar.slang)
• import "Foo.slang";
• __include Foo; / __include "Foo.slang";

resolved like #include: relative to the including file, then through the -I directories, recursively. A module that is not a file on those paths is provided by the compiler itself (or fails there with a proper diagnostic), so it is skipped, with a note in --verbose mode, instead of the hard error #include gets. Non-Slang sources are unaffected; the Metal toolchain-header exception still applies to #include only.

Testing

Linux, Slang 2026.20, SPIR-V, in the RTX Neural Shading SDK (entry points importing module chains three levels deep):

• steady state: no recompilation
• touching a module imported by two optimizer entry points recompiles exactly those two permutations
• touching a module imported by the training kernels and self-tests recompiles exactly those entry points, including through an import inside a #if and through an imported module that itself imports the touched one
• the #if 0 #include workarounds could be removed from the SDK shaders

🤖 Generated with Claude Code